With the development of molecular biology, the opportunity to perform gene (DNA) analysis has rapidly increased for various purposes. For this reason, in a gene manipulation technique of working on DNA strands or RNA strands in vitro according to the purpose, various enzymes having various activities are required. In addition, the current gene manipulation technique is not established without these enzymes.
In the gene engineering technique, various DNA-related enzymes have been used heretofore. As an enzyme that cleaves DNA, an enzyme that specifically recognizes a base sequence and cleaves DNA and an enzyme that recognizes a steric structure and cleaves DNA have been known. Among these, an enzyme, which is referred to as a restriction enzyme, has been frequently used as the enzyme that specifically recognizes a base sequence and cleaves DNA and generally recognizes 4 to 8 bases in a specific base sequence of a double-stranded DNA and cleaves the DNA. Meanwhile, as an enzyme that specifically cleaves a single-stranded DNA, an Si nuclease derived from Aepergillus oryzae which is an endonuclease that acts on a single-stranded DNA or an RNA to be decomposed into a mononucleotide; a P1 nuclease derived from Penicillium citrinum; and a Bal31 nuclease derived from Alteromonas espejiana are known and are commercially available.
In addition, in a case where a damaged base is present in DNA strands, Endonuclease V (Endo V) is known as an enzyme that recognizes the damaged base and specifically cleaves the 3′ side of the damaged base (Non-Patent Document 1). In regard to Endonuclease V, for example, Endo V derived from Escherichia coli is commercially available as an enzyme for gene engineering (New England Biolabs, Ipswich, Mass., USA). Further, oxidative abasic damage caused by oxidative damage of deoxyribose in DNA strands is known and Endo IV derived from Escherichia coli or human abasic endonuclease (ApeI) is known as an enzyme involved in the cleavage (Non-Patent Document 2).